Despite not making a single start since returning to Millwall, Tim Cahill has helped the club “massively” in their push for promotion, according to defender Jake Cooper.The Australia international has only made substitute appearances since arriving back in south London in January, where he started his footballing career 20 years ago.It’s been difficult for the 38-year-old to find a place in Neil Harris’ starting line-up, which has been changed just once over the last 10 games.From extras.The Lions are now a point off the play-offs following a 2-0 win over Bristol City at The Den on Saturday, in which Cahill came on for the last seven minutes.Cooper says the experience and leadership coming from both Cahill and the likes of captain Steve Morison have had a big impact off the field.“I’ve learned a lot from Steve [Morison] here last year, and then Timmy adding to that this year has been another level,” said Cooper.